Posture pillow



FIG. 1 is a front-elevational view of a posture pillow, showing my new design;

FIG. 2 is a top-plan view thereof;

FIG. 3 is a bottom-plan view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a left-side elevational view thereof; and

FIG. 6 is a rear-elevational view thereof.

The dash lines in the different views represent stitching. 

The ornamental design for a posture pillow, as shown and described. 